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When and how do I align with the runway during an offset ILS approach?
In X-Plane 11, when landing an A330 on 04R at Nice (LFMN) on an ILS approach, the aircraft is brought perfectly to the end of the runway but because this is an offset ILS the aircraft is at about 2° to the centreline.
My question is at what time and with what technique (rudder or aileron) should the aircraft be aligned with the centreline? I always seem to over-adjust and struggle to avoid wing tips touching the ground.

......are you actually doing this for real? Or in a simulator? Certified FSTD, or home computer game? If anything but that last, what does your instructor have to say about it? How about the pilot monitoring?

Yes, all at home using a simulator (X Plane 11)

Looking at my old approach plates, the ILS for Rwy 22R at KJFK of 24 JUL 1998 had an inbound course of 220°. The runway centerline was 224°, so a 4° difference. Decision height was 250'AGL.
In the 747, if we broke out before the decision height and had a clear look at the runway, we would in a shallow coordinated turn decrease our heading so as to intercept the runway centerline course visually and then we would visually turn onto and track the centerline.
The difficulty was when it was foggy, and all you could see near or at the decision height were the approach lights but not the runway sufficiently to visually acquire its course. You knew you had to correct to the right, but the tendency, at least for me, was to over correct because the approach lights were seemingly considerably off to the right, the more so the lower you were when you first saw them.
In the 747 you can safely use a 5° bank without dragging anything. As I remember the first thing to drag would be an outboard engine pod, but whatever. Thus, even up to the 100' call of the radar altimeter, a coordinated shallow bank would get you lined up, but you needed to be quick about it as your groundspeed would be around 160kn.
The first time I made the approach under those minimal conditions, I did indeed over correct. My choice going into the flare was enough left rudder and aileron to get the nose to the runway heading and then maintaining the 5° bank to slip back to the left. Having made the over correction that first time, I was careful not to repeat the mistake.
It's been nearly 20 years since I last shot that approach. I looked at the approach plate of 08 MAR 2012 on the Internet, and I see that they've straightened things out. The approach course is 222°, the runway centerline course 223°. Decision height is still 250' AGL.

Thanks, Terry. I wasn't sure whether breaking out of the ILS course to intercept the centreline of the runway earlier would be good practice even though it does seem the logical thing to do. I will test out the procedure on my PC simulator.

I imagine you are asking this on the context of a home simulator game. Nevertheless the flying technique in the real world should be applicable.

(...) avoid wing tips touching the ground

My advise is, practice crosswind landing. Specifically, practice the crabbing technique. Use tiny but frequent inputs on the rudder for heading adjustment. Ailerons should be used to maintain wings level.

I always seem to over-adjust (...)

That is because you are using one big adjustment. You should be using tiny but frequent adjustments on the flight controls.
And practice in a Cessna 172 first. Yes, even if your goal is to land an A330 in the simulator game. Then gradually move up to faster airplanes.

Thanks, Kevin, this answers my question. I need to start earlier and make many small adjustments, and practice crabbing.

OP has clarified that this is about X-Plane 11 at their home.


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Is this a Convair C-240?
This aircraft is at Dodson International in Rantoul, KS. I've boiled it down to Convair. Looks most similar to a C-240. And does anyone recognize the livery?

It has USAF painted in the top of the right wing, as can be seen from satellite at 38.541248,-95.103554

Btw... one of these aircraft with rectangular windows.

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How does EMAS reduce damage in case of an aircraft overrun?
I saw a report about Mike Pence's plane overrun today on Twitter link: Mike Pence plane overrun photo on Twitter.
As can be seen there is huge cracks and breaking of the runway but the plane was not damaged. According to twitter this is due to Engineered Materials Arresting System (EMAS). The FAA is adopting a plan to expand the use of this method for arresting overruns on runways that do not have enough land for a runway safety area (RSA).
I am interested to know how this system works. Is it similar to gravel runaway truck arrestors on the steep downhill roads? Do we have any specifications and test data?

FAA advisory circular 150/5220-22. Article on EMAS, Wikipedia. Somehow related: How do pilots use stopway, EMAS, clearway and displaced threshold?.

This answer by foot contains some of the information you are looking for.

If you read the FAA link in the tweet you link to it tells you all about it.

@mins, I checked FAA advisory circular 150/5220-22. It has most of pertinent info. Thanks.

There is a link in the FAA tweet you link to, you should probably read it.

EMASMAX® is the latest, most durable version of ESCO’s EMAS, developed with and technically accepted by the FAA. EMASMAX arrestor beds are composed of blocks of lightweight, crushable cellular cement material designed to safely stop airplanes that overshoot runways.
  - FAA Fact Sheet – Engineered Material Arresting System (EMAS)

So yes it's like gravel runoff areas, where the crushable material slows down the aircraft by providing resistance through the landing gear. The difference being this is a bit more engineered so you don't get bits flying up into the engines etc. like gravel would.
As for specs, the same link claims it can stop an aircraft going 80 mph but doesn't state a size of aircraft.

A standard EMAS installation can stop an aircraft from overrunning the runway at approximately 80 miles per hour.
  - FAA Fact Sheet – Engineered Material Arresting System (EMAS)

Thank you @Notts90. One would like to see new research on material which would behave more like a very dense viscose liquid/plastic with self repairing and self leveling properties. I understand why use of gravel-bed is not practical but this system has its own limitations.

A Piper Cub at 80MPH and an A380 at 80MPH are two very different propositions. I wonder toward which end of the spectrum that "80MPH" statement is aimed...

@FreeMan I had the same thought. I really hope it's the A380 end!

@FreeMan The FAA AC on EMAS design (AC 150/5220-22B) says the design is for the aircraft using the associated runway that imposes the greatest demand upon the EMAS. - so basically the fattest pig they expect to land there, at maximum weight. It also notes that the design models don't work well for planes that have a max takeoff weight less than about 25,000 pounds - i.e. "They're not designed or intended for stopping a Piper Cub. You should be able to do that yourself."

Good to know, @voretaq7, thanks!

@FreeMan, it is a huge difference in energy, but if you can get the same coefficient of friction, you'll get the same braking distance. And since the bigger aircraft has more wheels and higher pressure on each, it will crush more of the material and might get almost the same coefficient of friction. The design then mainly governs how thick the layer has to be so there is enough for the big aircraft to crush and impart the energy into.

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Are airline ICAO codes unique?
Tiger Airways Singapore's IATA code is TR while Tiger Airways Australia's one is TT, but the ICAO code for both is TGW. I thought that the ICAO codes are meant to be unique from one airline to another, not the other way around. Is this the only case?

From what I can tell they're the "same" airline, perhaps split off from the same company. They both use the same callsign "GO CAT"

From what I know, they have different ownership (i.e. different parent companies) but they each have the right to use the same branding by the holding company. I know about the callsign (I listen to live ATC way too  much often!)

Does this apply to IATA or ICAO?

There is no right or wrong, I was only asking. :)

ICAO three-letter codes are always unique. The official source, ICAO Document 8585, says the following:

1.2 The same designator will not be registered for more than one aircraft operating agency, aeronautical authority or service.
1.3 No more than one three-letter or telephony designator will be registered for each aircraft operating agency, aeronautical authority or services.

In your example, Tiger Airways Singapore only exists as a single airline in document 8585. The fact that they have an Australian division does not mean that it is a separate aircraft operator, and thus no separate ICAO code can be assigned.
You can find more rules regarding ICAO identification codes, including a complete list of every ICAO code in the world, in doc 8585: http://dcaa.trafikstyrelsen.dk:8000/icaodocs/Doc%208585/DOC%208585,%20Edition%20no%20149.PDF
Interestingly, British Airways seem to contradict the above rules with their seasonal "Santa" flights. Around Christmas, certain British Airways flights will operate with the XMS ICAO code (radio callsign "Santa"), instead of the usual BAW ICAO code (radio callsign "Speedbird").
In ICAO doc 8585, the XMS code is registered to "British Airways Santa", which I very much doubt is the name of a real company, so it does seem there are ways around the rules quoted above.


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Would an aircraft with contra-rotating propellers longer than the plane's wingspan be able to fly?
I enjoy taking the time to try and visualize how fictional aircraft might actually work in reality. Unfortunately there are some that seem highly impractical from an engineering student's point of view.
One in particular is the Bella Ciela from "The Place Promised in Our Early Days." It features a set of blade-like wings that protrude out front and deploy into contra-rotating propellers, sustaining flight after its jet-assisted takeoff. The blades spin much slower than a conventional propeller as well.

I can get by the closed-loop wing. The V-tail has no issues as far as I can see. My main concern is the large rotating blades that extend far beyond the wingspan of the plane. Taking the Bella Ciela's design out of the equation and focusing on concepts alone..

How feasible is it to use a propeller larger than the wingspan? Is there any law of physics that prevent this configuration?
What immediate consequences would be seen in the airflow behind such a large propeller? Would the wings aft of the flow still be able to produce stable lift?
The blades remain flat when stowed and act as an additional lifting surface; but I assume one could position them so that their loss of lift doesn't affect the balance of the plane (like in the sketch, with them centered)?
Without twist, can a propeller still provide efficient thrust? Could you reproduce the twist's effect by instead varying the length of the blade's chord from root to tip?
Are there standard equations for calculating thrust and drag of a propeller that does not have twist? Or of a propeller in general?

I can already see how drag would be a huge issue with spinning something so big. Is there a limit to how long propeller blades can get?
My apologies if I am asking [too many] questions that do not fit this board's criteria. This is just a concept that has had me Googling around for the past few hours. It's neat, and I hate dismissing things as just art without at least trying to justify them.

How would you land and take off in that thing? I guess I wouldn't want to board a plane that is sitting on a carriage longer than the wingspan. It would feel like boarding a flamingo.

Is this an airliner concept. One thing you would have to with such a large propeller is a more risk of bird strikes. Looks like more competition against my airplane design.

@Alexander If I'm reading it right the idea would be to take off and land with the blades in the "wing" configuration (top picture) with them being deployed into "propellor mode" once airborne.  Obviously there would need to be an additional source of thrust for take-off and landing.

There would be some practical engineering problems with a design such as this. I recall talking to an engineer who worked on the Bell XV-15 who explained that one of their major issues was that steel wasn't strong enough to make the rotor hubs, and having to come up with something that would work. I suspect that in an aircraft such as the one you've described the hubs would have to be made from unobtanium - an ideal substance for such use whose only drawback is that it doesn't exist.

@ethan Are you sure there'd be more risk of bird-strikes? Sure, the huge props sweep out a very large area but they're also moving slower, which means that, compared to a smaller, faster propeller there's much more chance of a bird passing through the swept area without getting hit. I don't think you could guess the trade-off between the two factors without sitting down and doing the math.

I'm voting to close this question as off-topic because it is about fictional aircraft from Science Fiction, and has no relation to real aviation.

@abelenky while it may be about a fictional aircraft, I think it asks good specific questions, and Peter provides good answers that are certainly on topic here.

My problem with that design is, how do you counter the propeller's massive torque? With a regular fixed-wing plane, it's just a little aileron trim as the ailerons would be acting much further out than the span of the propeller, so less force creates more counter-torque. Here, the rolling control surfaces would be fairly hard-pressed to keep the deck of the aircraft level with the ground during cruise.

"Massive torque" is balanced with contra-rotating rotors.  Sketch isn't bad.  Reminds me of "jib and jigger" sailing rig (mainsail is dropped in higher winds).  My fiction had the "mains'l" as a swing wing with Blackbird jet propulsion.  This may work, need to find an application to make it real.

Sounds like you need to ask this question to a bumble bee. Once they tell you how they are able to fly then come back here and report to us the answer. Until then???

Short answer: This design will probably work, but it will not be very efficient. It can be tweaked into flying, but when you start tweaking, you would continue such that the outcome would look differently.
Now let's look at your questions one by one:

How feasible is it to use a propellor larger than the wingspan? Is
  there any law of physics that prevent this configuration?

There is no law which forbids such a large propeller. In order to create thrust, you need to accelerate a mass of air backwards. The larger the propeller, the smaller the acceleration needs to be for a given thrust, since a higher mass flow is available. This makes large propellers inherently more efficient, but larger blades are heavier and also produce more friction drag, so the sweet spot is at propellers which are quite a bit smaller than the wings of the aircraft they are attached to.

What immediate consequences would be seen in the airflow behind such a
  large propellor? Would the wings aft of the flow still be able to
  produce stable lift?

Since the acceleration provided by the propeller to the air mass is small, the wings behind them would fly in almost undisturbed air. The lift will wobble a little over time, because the boundary layer flowing off the propeller blades will produce a cyclic variation in dynamic pressure on the rear wings. This will, however, not impede their general capacity to create lift.

The blades remain flat when stowed and act as an
  additional lifting surface; but I assume one could position them so
  that their loss of lift doesn't affect the balance of the plane? (Like
  the sketch with them centered)

At slow speed it helps to have more wing area for lift creation. Note how much the fowler flaps of an airliner move backwards to increase not only the wings camber, but also its area. Using two wings flying in formation would allow to give the rear wing a much higher angle of attack and to use the gap between them to refresh the rear wing's boundary layer like it is done in slotted flaps, so in combination their lift would be higher than that of one wing of the same area. The long, narrow propeller blades of this fictional aircraft look too flimsy, however, to be of much use in adding lift: They would break off at a fraction of their potential lift if built with existing materials.

Without twist, can a propellor still
  provide efficient thrust? Could you reproduce the twist's effect by
  instead varying the length of the blade's chord from root to tip?

Good that you added "efficient"; this changes the answer from a "yes" to a "no". Only with twist would the local angle of attack be close to the optimum, but even without twist, thrust will be possible. Then the goal should be to pitch the whole propeller blade optimized for the outer 30% of its span. The thrust from this will create a strong root bending moment, however, and I doubt again that the slender prop blade will not break off. If you try to create thrust closer to the center, the outer part, which is flying at the highest dynamic pressure, will create substantial drag, requiring lots of torque, and again the propeller will break off, but in a different direction.

Are there standard equations for calculating thrust and drag of a
  propellor that does not have twist? Or of a propellor in general?

Yes. The first good ones were published by A. Betz and L. Prandtl in 1919, and the latest substantial improvements were added by Larabee. Incidence can be prescribed, and so can be set constant over the whole span. If you can run a copy of Mark Drela's XROTOR, you can try for yourself.

As an addendum: with such a long propeller, the tips will be moving much faster than the root. Props generally want to keep their tips subsonic; the changes in airflow and the structural stresses when they approach Mach speeds are... problematic. On a prop that long, either the tips will go supersonic, or the roots are very slow. This means that you'll have a lot of twist along a sizeable section of prop to produce any real thrust, which in turn may cause drag problems.

How would long prop blades compare to the long blades of a helicopter? They can be very long and thin but don't break off. They provide both lift and propulsion.  They have the same problem with avoiding supersonic tips but those problems have solutions. I assume there would be a big difference being vertical rather than horizontal.

@TomMcW: Good comparison! Helicopter blades have a very solid root and constant chord over their span. The props in the picture have very thin roots and more chord at mid-span, so they will produce higher root loads. Also, the rotation stretches helicopter blades horizontally. Here, when used as wings, no such help is available, and flutter and bending will take their toll. Also, the lift coefficient of a symmetrical or reflex helicopter blade produces much less lift per area than the slotted wing possible with the two blades here.

@TomMcW 1) Helicopter blades suffer more loads (think of the air pushing on the prop tip as it rotates in front of the helicopter, creating an axial load that could potentially buckle it), 2) helicopter blades usually don't do too much with twist, because they use a cyclic to change the AoA of the blade to achieve control of the helicopter. Variable pitch props on planes also have significantly less twist than a static prop, but that has more to do with a static prop having different regions optimized for different speeds, whereas vpp are adjusted to get the best thrust for current airspeed.

Let's talk about the propeller size for a minute and ignore the aerodynamics of the rest of the vehicle as they have been covered in another answer.
Remember that the tips of a propeller spin faster than the roots. Even though the whole propeller spins at the RPM the tips must cover more distance the roots and are thus moving faster. This can create a supersonic tip situation which can be a problem in and of itself. You can find some coverage on that in this question. To keep the tips subsonic in this craft you would need to spin the propeller slowly which may not create enough thrust to fly the plane.

It all boils down to physics.  What we are looking at here should be a helicopter.
Yes, absolutely, with contra-rotating rotors it would fly.
But now we must look at the demands of flight, how much force is needed to overcome
gravity and how much is needed to overcome drag while producing velocity.  It becomes
clear the design is backwards, with tiny wings and an oversize propeller.  If it flew as a helicopter, notice it would need only a slight forward tilt to move forwards.
This relationship was found while studying gliders.  There is very little frontal area compared
with area as viewed from the bottom.  That, along with streamlining, allows the glider to move forwards through the air while only dropping slightly (flugzeug gefallen).  Once in motion, the wing generates lift even more efficiently (segelflug).

Now birds have it right.  They swing their wings as large efficient propellers.

Such aircraft already exist, with contra rotating propellers that extend beyond the wings:
V22 Osprey
V280 Valor
AW609
One non tilt rotor that never made it to production:
Vought XF5U
It showed great promise, especially for it's STOL characteristics, but had the misfortune to be in design when jet engines came out.

-1; none of those aircraft have contra-rotating propellers - they each only have one propeller per shaft. "Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque."

Really? Aircraft such as the P38 and F82 are referred to as contra rotating, because the propellors rotate in opposite direction to cancel torque. The effect is the same, regardless of whether the props are stacked or not.

Nope, P38 is counter rotatating.  Look it up.

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Where can I find the active time of a MOA on the VFR chart?
I am trying to find out the time when the HILLTOP MOA is active and its elevation. Where is this information located in a VFR chart?

It's in a table on the border of the sectional.  Looking at the Chicago sectional, this is along the top....

Just be advised, published "normal" hours are not the same as active.  They generally aren't hot continuously.


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How can I find out if the government paid to build a runway?
I've heard rumors that the government paid to build a runway at a residential fly-in community in the mountains of North Carolina to have it available as an emergency landing strip.  I would appreciate suggestions of how to find out.  I tried calling the FAA but with the automated system, I found it impossible to reach a human being.
Thank you!

Funding sources for construction projects does not seem like an Aviation related question to me.

The question was in regards to a RUNWAY.  Somewhat Aviation-related, wouldn't you agree??

I would.  Airport construction funding and compliance with grant assurance stipulations are quite on topic in my opinion.

The FAA gives funds to airports through the Airport Improvement Program (AIP) and that could include runway improvements. It's public money so the information is also public and should be in the Excel files on that page. If that isn't what you need, you can always submit an FOIA request to the FAA for all information they have about the airport.
It's also possible that you could get more information from the state or county. They usually have at least some input into airport construction, because of local zoning laws, easements and so on. Even if the rumor is false and the runway is built on private land and paid for with private money, there may be county planning or landowner records. But that's definitely beyond the scope of this site.

Local newspapers/etc are another good source since you'll see various govt officials and politicians bragging about tax dollars at work.

Normally a call to the local FSDO will yield the current expenditures, and the planned expenditures.  A FOI may be needed for all the information, which is often folders of studies, engineering plans and correspondence.

My thanks to each of you who responded.  I appreciate the information and will take it from here.

@Emma K. I'd be interested to hear what you found and how you did it.


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Does flight training have any impact on my H1B visa?
I'm on an H1B visa, working in the IT industry and I need to know if I take flight training after getting an AFSP clearance from the TSA, does that affect my current visa or IT job?

Having flight training has no effect at all on your visa status. It's actually the other way around: your visa status can determine whether or not you can have flight training. But you can definitely get flight training with an H1B.
And flying has no special impact on your job: how you choose to spend your free time is none of your employer's business. There could be some very specific scenarios where flight training and work intersect, e.g. if your company is in the aviation sector you might be able to get them to pay for training. Or if you're a very senior executive at a very large company then the Board of Directors might have concerns about you spending your time on 'risky' activities. But otherwise, flying has nothing at all to do with your work.

flying has no special impact on your job: how you choose to spend your free time is none of your employer's business In most cases, and for most people, yes. I have talked to people, particularly in the financial sector who are specifically barred by employment agreement from participating in many outside-work activities. Honestly, I don't think pilot training would be one of the barred activities, but the statement is a little bit too blanket. i.e. Don't let random strangers on the internet get you fired & risk deportation. Be sure it's OK with your employer.

Freeman is correct. Some employers set restrictions on "high risk activities" for (usually some of) their employees to mitigate corporate risk in case they die or become long term disabled. Flight training may or may not fall under such depending on the whiles of some HR flunky (more often it's meant to stop people from bungee jumping, parachute jumps, and rock climbing).

I talked to one of the flight school and they said I can start ground school with part 141, and when I checked the link provided by pondlife in the above message, it is indicated that h1b visa holders are eligible for part 61, does that part 61 or part 141 really matter? or can I take part 141? please advise, Thanks in advance!


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Where is the best centre of gravity for planes like the Berkut 360?
I am making an RC plane similar to the Berkut 360. Can anyone please suggest where is the best location for the centre of gravity for such a plane? (With explanation please)

I found this calculator that appears to support canard aircraft.

I cannot tell you the exact location or the locus of the CoG for the current aircraft but I can provide you a method that you can use to find the appropriate location for the aircraft to be statically and dynamically stable in flight that you can use for any future aircraft.
I'll put it simple, CoG alone means nothing, you need to know the Neutral Point (NP) of your aicraft, that is the point that if you place CoG there you'll have neutral stability (i.e. the airplane will not tend to increase or decrease a pitch up input you give with your RC). The NP is considered in practice the aft limit of your CoG.
What matters in terms of stability and control is the distance of CoG from NP that is given by what we call Static Margin (SM). An empirical rule for SM is given as
$ SM \equiv \dfrac{x_{NP}-x_{CoG}}{\bar{c}} = +0.05\ \ \ ...\ +0.15 $
where $c$ is the mean aerodynamic chord (MAC) and $x=0$ is at the leading edge of the wing's MAC.
Now, a general method to compute the NP is to use an open-source Vortex-Lattice Code like AVL of MIT (Mark Drela) (http://web.mit.edu/drela/Public/web/avl/). If you know the geometry of your airplane, and of-course you know it since you're building it, you can make the model of the airplane and with AVL you can obtain the NP from an analysis.
If you are lazy, and need an empirical and fast way to compute your NP x location then you ca.. Whoops! winglets as Vstabs... I am not sure about the validity of empirical formulas for this aircraft and you should do the algebra of flight mechanics to deduce them. It's cool but a VLM code is more general.
If you find the $x_{NP}$ you can find the $x_{CoG}$ values that satisfy longitudinal static stability criteria and then with trial and error decide what value in this range gives you the best flying experience as there is no "best" value in engineering if you don't specify the optimization constraints.
Good luck!


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Was there any progress in ramjet-powered helicopters after 1960?
It seems in 1950's some countries investigated production of helicopters powered by ramjet engines on rotor tips - examples include American Hiller YH-32 Hornet or Polish JK-1 Trzmiel. The enthusiasm was short-lived - high fuel requirements, a significant load to the power transmission system, noise and high visibility on battlefield were significant disadvantages that ended the research programs which I know of.
Still, that's over half a century ago, and the technology has progressed quite a bit since then so maybe some technical problems of that epoch are now past? - The ramjets are small, lightweight and quite simple in construction, so despite the disadvantages the technology doesn't seem like a total dead-end. Was this line of helicopter propulsion investigated further? Could someone provide a progress report - if there is anything to report? Or is this research branch still dead, with no attempts to revive it?

Tip jet rotors are still being developed, none of them are ramjet powered as far as I know. The Dragonfly DF1 is tip rocket powered, while the Pegasus uses air jets powered by a conventional engine.
Ramjet technology has not improved, so the cases for using them on rotor tips has not changed. They are still too heavy, thirsty and noisy.

Ramjets aren't particularly heavy, especially when designed for subsonic flight speeds. But at those speeds they are horribly inefficient.

Short answer: No.
Or at least, nothing that's been demonstrated that I'm aware of. Whether there have been experimental R&D aircraft or developments, I'm not sure - but I can't find any.
The simplest reason is just because there's no need for them - they offer no real advantages over a conventional internal combustion or jet engine, so as with so much else in aviation we stick with the tried and tested "we know it works" product, unless there's a good reason to change.
It's not necessarily that tip-jet helicopters are a complete dead end in terms of development, just that we don't see any advantages to be gained from them.

I'm reading a book right now that talks briefly about flight testing the Hiller. As I recall, it was tough to get both engines started at the same time, and if one of them cut out,  was a pretty violent affair. It was also an environmental disaster, with horrible fumes and noise. It was an interesting experiment, but it had no real world application at all. There still doesn't appear to be one.

This particular idea has been abandoned for several reasons.
Tip-jets that put engines on the tips themselves - "hot" tip-jet, unlike "cold" tip-jet where a central turbine sends compressed air through the blades to be ejected at the tip - cause lots of drag, in addition to being very noisy. While the noise problem may have been lessened to an extent by further R&D, the drag problem is more or less unavoidable. This is why hot tip-jets have mostly been abandoned by now.
As an aside, cold tip-jets have been used to reasonable success with the Djinn helicopter: https://en.wikipedia.org/wiki/Sud-Ouest_Djinn
While it has much less autonomy than equivalent helicopters due to lower efficiency, it was also much lighter and much easier to pilot, and enjoyed some commercial success. With a heat exchanger to heat up the outgoing air with turbine heat, a newer helicopter could have had similar autonomy to a conventional one, the slightly lower efficiency being compensated by the lower mass. However designing an adequate heat exchanger would have been considerable R&D work, so no-one seems to have bothered with it as conventional helicopters were already doing the job.

But specifically for tip-ramjets, there is another, even worse problem: ramjets are efficient only above the speed of sound, and propeller blades are very inefficient and immensely noisy when the tip of the blade is supersonic. So you either loose considerable efficiency by having the ramjet operate below optimal speed, or you both loose considerable efficiency and make so much noise that it is physically dangerous for people nearby.
While not a tip-jet or a helicopter, the Thunderscreech showed what happens when you try to use supersonic propellers. It made mechanics literally sick, and could even knock people out from the sheer noise.
https://en.wikipedia.org/wiki/Republic_XF-84H_Thunderscreech
The Soviet (and now Russian) Tupolev TU-95 bomber also has propellers that can go slightly supersonic, to get extra thrust at the expense of efficiency when going at max speed, and has been known to be detected by submarines due to the propeller noise.


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How accurate is the barometric altimeter in the Tu-154?
If the Smolensk disaster was to be traced down to a single decision (other than attempting landing in the first place), it would probably be the choice of radio altimeter to control altitude over a very unfortuitously shaped terrain (a wide valley, with steep slopes). This made the airplane to descend to 80 meters above the bottom of the valley, instead of 80 meters above the runway located 60 meters higher.
Someone mapped the black box recordings of the navigator's altitude readouts to speed and terrain profile, interpreting them as barometric altimeter readouts and it came out as an unreasonably bumpy ride (the orange line). I tried to follow up with mapping these same readouts at the same intervals, but relative to ground surface - treating them as radio-altimeter readouts - and it follows the blue line; judge for yourself which can depict a large passenger plane trajectory more accurately.

An unbiased comparison would include both advantages and disadvantages of the two types of altimeters. In this specific case (unknown, uneven profile terrain) the one main disadvantage of the radio altimeter is obvious: it doesn't provide accurate information about altitude of the airplane relative to the runway. I wonder though, what redeeming properties does it have - what are the advantages (if any) of using a radio altimeter over a barometric altimeter during landing - any inherent flaws of the barometric altimeter, like accuracy, reaction speed, or such, in which one type excels over the other?
(yes, I'm asking for a biased comparison; one with focus on superiority of one of the other. I realize both have their correct applications, both have strengths and weaknesses, applications where one or the other is better. Here I'm specifically asking for one side of this argument; half of the full image; look at it not as "why is A better than B" but "which traits of A are better than B")

The Smolensk machine crashed because of two bombs' explosion, at first one on the left wing (this made the liquid for navigation run out so that roll/pitch/yaw was no longer possible) and then a 2nd one beneath the seat besides the President, just before hitting the forest.

A barometric altimeter is required to meet certain operational standards for use in an aircraft under instrument flight rules. We talked a little about this in another question with references to the relevant FAA requirements for the instrument.
I'm certain there's an equivalent in the Polish regulations, and while I don't know where you'd find it I would bet it's broadly similar in its requirements.
A radio/RADAR altimeter is typically accurate to within 20 feet within its operating range (typically <= 2,500 feet AGL). There are varying TSOs for radio altimeters, so you'd have to look up the standard a specific unit was built to in order to get exact numbers.

One of the core issues underlying this accident which you highlighted in your question is that a barometric altimeter and a radio altimeter are two different devices, measuring two different things, so it's not really reasonable to compare them.
Barometric altimeters measure altitude above a standard reference (usually sea level) by using a known/standard pressure lapse rate (~1 in.Hg per 1,000 feet) and measuring the difference in pressure at the instrument.

The readings given by a barometric altimeter are affected by weather conditions (mainly temperature), so the displayed altitude may be 'incorrect' (relative to say GPS altitude above mean sea level).
The readings given by a barometric altimeter are not affected by the local terrain, so peaks, valleys, and tall buildings won't change what it shows.

Radio altimeters measure the distance to whatever radio-wave-reflecting object is below the unit (typically "the ground" - whatever terrain happens to be under you) by detecting how long it takes a radio pulse to be reflected back.

The radio altimeter reading is not affected by weather conditions (temperature) as these don't affect the pulse reflection time.
The radio altimeter is affected by local terrain (peaks, valleys, etc.) as this changes the distance the radio pulse has to travel.
The radio altimeter reading is affected by any object that reflects radio waves (buildings, other aircraft passing below you).
The radio altimeter reading may be affected by "slant range error" just like DME, (in practical terms this is less of an issue for radio altimeters: The radio altimeter points "straight down" so the slant range error is generally small unless the aircraft's pitch or roll attitude is extreme).

So to directly answer your question, barometric and radio altimeters aren't comparable in the way you're asking: Because they measure two different things it's not possible to say one is "superior" to the other. They are different tools, serving different purposes: It's incumbent on the pilot to be aware of the limitations of whichever tool they happen to be using at the time (and to ensure that they've selected the correct tool for the task at hand).

Imagine you're about to land on perfectly flat frozen sea surface, thick ice. They will display exactly the same thing; altitude over the sea level and distance to the sea surface. Weather conditions are uniform and you got the local sea level pressure from a ground station; the sea is big, a perfectly flat desert of ice, so you can land anywhere safely, but it's night and no ground lights; you must depend on the instruments. Which one would you use?

@SF., that would be a very special case where the radio altimeter would provide the desired data and the barometric one presumably would not due to lack of reference measurement (QNH or QFE) near the landing site. But when landing on airport, such reference measurement is always available while in most cases the terrain is uneven enough to disqualify the radio altimeter and relegate it to the role of auxiliary instrument for checking terrain clearance.

@JanHudec: So in general case using radio altimeter for landing approach would be a rather... weird choice?

@SF., yes, it would be weird choice. Still it seems that was exactly the choice made in this accident (and is, AFAICT, mentioned in the investigation reports).

A radio altimeter is probably better because of its independence from weather-related pressure systems which barometric altimeters are really horrible at. There are many small pressure variations in a given area which the barometric one cannot compensate for all the time. The radio altimeter works batter in this area because a pilot would not need to reset it as often and when it encounters weather, it will not mess up.

Using radio altimeter was important contributing factor in the accident and was really unusual procedure and clearly the wrong thing to do.


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Can the acting PIC sit in the back?
For a planned ferry flight under FAA Part 91, this is the scenario:

Two of us, let's call us A and B (rated pilots for that airplane), want to sit in front and do the flying.
A highly experienced pilot, C, will accompany and supervise the flight, sitting in the back seat.

Insurance insists that C be acting PIC throughout the flight.
At the same time, insurance has explicitly said that C can sit in the back while doing so.

This doesn't accord with C's own understanding of what is legal in an airplane that only requires one crew member. My own reading of who can be PIC doesn't say anything about where in the plane they have to sit.
So the question is: Can someone act as PIC while sitting in the back seat in a single-pilot airplane?
Relatedly, if the answer to the above is Yes:

Suppose B is a CFI
A manipulates the controls.
Can all 3 pilots log PIC time?

A is sole manipulator of the controls;
B provides instruction;
C is acting PIC?

Is C comfortable with being in command while in the backseat? (seems implied by the question, but you don't mention it)

If A&B are rated pilots for the aircraft, why is the insurance company requiring C be the PIC? That sounds really odd to me, unless this is a ferry flight with some strange requirements (like flying across the Atlantic or to Hawaii)...

@RonBeyer  It's not that uncommon. Let's say A has a multi-engine commercial rating, and B is a CFI with multi-engine. But while A and B may both have time in piston twins, this aircraft may be a turboprop. A is the new owner, B is A's preferred instructor and C is a rated pilot with sufficient turbine time/time-in-type to keep the insurance company happy. The insurer will typically require new-owner A to fly with someone like pilot C for some number of hours before operating solo.

Can the acting PIC sit in the rear seat?
There's no regulation or FAA interpretation I can find that requires the acting PIC to sit in a seat with access to the controls. For flight instruction specifically, 14 CFR 91.109(a) requires dual controls (usually) and the instructor must be at a "pilot station" (14 CFR 61.195(g)(2) and Williams interpretation, 2018). So no instructing from the rear seat.
Of course there's also 91.13 (careless and reckless operation). That's a deliberately broad regulation and I have no idea how risky your operation might be considered. If A and B already have experience in the aircraft and they'd be fine to fly it without C anyway (from the FAA's point of view), then arguably there's nothing careless or reckless happening. On the other hand, if something goes wrong and lawyers get involved to determine liability then it's anyone's guess what could happen.
Can all three pilots log PIC time?

A: yes, as sole manipulator of the controls (61.51(e)(1)(i))
B: yes, if they're giving instruction (61.51(e)(4)). That means A and B need to log it as instruction time in their respective logbooks (61.51(h)); they can't just say "let's call this instruction so we can both log PIC".
C: no, acting as PIC doesn't automatically allow you to log PIC time. 61.51(e)(1)(iii) doesn't seem to apply here because in your scenario neither the aircraft type nor the operation require a second pilot


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Is propeller wake turbulence quantifiable based on operating conditions?
I know the propeller does work on the air and thus the flow behind a propeller is higher than the airspeed. However, what is the quality of this flow? If I were doing a heat transfer analysis of an object behind a propeller, other than the accelerated flow speed, the effect of turbulence would matter too, where turbulent flow will contribute towards higher forced convection. I'm not sure how to quantify the added turbulence from a propeller. Is there a simple rule of thumb?

I have a question (and forgive me if I’m wrong), but outside of pusher props, most propellers are immediately in front of things like engines, cowlings, fuselage, wings, etc... wouldn’t these things immediately impart their own turbulence patterns on the airflow driven by the propeller? And if this is the case, then the turbulence would be different from one configuration to another, even provided the exact same engine and prop, right?

@AaronHolmes yes, you're right. But I think it's possible with larger props, the ratio of the engine aeroshell radius to the prop radius is quite small (otherwise it would impede flow and reduce efficiency as well). And it's quite possible that the "swirl" or patterns generated by the propeller wake hold for sometime until they reach these components that heat transfer is being studied on. I could be wrong and maybe this is an impossible questions without the aircraft geometry like you say, though. Part of the reason I'm asking..

As a rule of thumb, use fully turbulent flow at the elevated speed of the propeller wake on all surfaces wetted by it. The speed increase will result in higher friction drag compared to the propeller-free case and results in a drag increase that looks about right.
A very interesting paper on the efficiency of an installed propeller can be found here. By comparing the gliding qualities of a Luscombe 8E with drag in level flight, the authors measured the drag increase of the airframe caused by the propeller wake. A drag increase of 30% from the propeller effect was measured, resulting in an overall propeller efficiency of only 62% when the propeller alone had an efficiency of 81%. The paper cites another result where the installed propeller on a Bellanca showed only 58% efficiency, but the paper is unavailable on the Web.
For pretty pictures you can consult this paper which analyzed the propeller wake - wing interaction on a C-130 J with 6-bladed Dowty propellers using CFD. The picture below is taken from this paper and shows surfaces of the same vorticity.

CDF simulation of propeller-wing interaction. The tip vortices of the single propeller blades can be seen impinging on the wing surface which suggests that local flow speed will vary with the frequency of the propeller wake hitting the wing. Also, the local turbulence is higher on the side of the down-moving blade. However, most of the wing surface shows only a minor increase in local turbulence, judging from the vorticity of the wing wake. Note that the engine air intake - nacelle intersection contributes a wake of its own which technically must be added to the propeller effects.
However, I doubt those details can be accurately subsumed in a simple rule of thumb; therefore I recommend to use a constant, elevated flow speed on all areas wetted by the prop wake.

Thanks, this is exactly what I'm looking for!

Curious if increase of lift from prop wash was factored in, enabling a lower AOA (of entire plane).  This would recover some drag efficiency.  Data for wing mounted pusher props would make a great addition to this study.

@Good point, but lowering the AoA in the linear range does not change non-lift-dependent drag much. On the other hand, the now distorted lift distribution with propeller effects should lower the Oswald factor of the airplane, adding a bit of induced drag. Hard to say what the net effect is – probably negative at low and positive at high AoA.


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If alternator fails and I'm running on battery power, what equipment can I turn off to conserve power?
For a PPL, if the alternator goes out and I'm running on battery power, the typical advice is turn off what you can to conserve power. But what exactly is safe/unsafe, or order in which to turn off equipment?
I fly a Piper Cherokee. So in that case, I'm thinking the order in which I can do things is as follows:

Call out that I've had an alternator failure, either to traffic or ATC.
Turn off lights
Turn off avionics
Turn off pitot heat (Technically where I fly, it's blazing hot and we never need pitot heat, but I'm listing it as number 4 as it's more of a flight functionality/safety issue)
Fuel pump?

My concern is #5. Cherokee is a low wing and when we come into land, we always keep the fuel pump on. So I'm guessing it's never okay to turn off the fuel pump and just fly the plane. However much time I get with the fuel pump, I'll take.
Once all power is gone, then I can proceed with power-off landing procedures.
Is this the right way to think about it?

A comm receiver needs lots less power than transmitting. Depending on circumstances, keeping a comm receiver & your transponder powered might be useful. Don't play 20 Questions with ATC, though -- that can drain your battery quickly.

See also this thread for discussion of the mechanical fuel pump in the PA-28: https://aviation.stackexchange.com/q/79542/7532  Just losing the electric pump won't starve the engine of fuel.

The fuel pump should be turned off on the climb check.  Turn it off, it is only used as a backup in case the engine-drive fuel pump fails.

Any advice you get is situational and what is discussed could not be the best advice in a different scenario.
There is an emergency procedure in the PA28 checklist that covers electrical failures.  I would run that checklist and I agree it says to reduce electrical loads

If I am in day VFR in class G or E airspace (United States).  I would turn off all lights, radios, transponder, pitot heat, fuel pump, etc.  As I got towards my landing airport, I would turn on the radios and self-announce my intentions.
If I am in class C or D airspace or already talking with approach control, I would let ATC know and keep one comm radio on for communications.
If I was at night, I would keep on my position lights but most likely turn off my strobe lights.  I would also land at the nearest suitable airfield.

Reading about the systems in the POH, the PA28 uses roughly 30 amperes to power nighttime equipment with radios on.  Perhaps, someone with knowledge of a 12-volt battery in a Cherokee could provide a suitable operational time in that condition.

I experienced this once in a night IFR training flight in VMC. The aircraft was a Cessna 172RG Cutlass. I was on an ILS when I noticed the low voltage light on. I decided to wait until missed approach to troubleshoot.
As I went missed, I checked the low voltage light again at full throttle. It was still on. After leveling off, I notified my CFI of the problem. We pulled the checklist and attempted to reset the alternator. No improvement. So we notified ATC of the issue and asked to return to our home airport, not far away. Then we tried to reduce electrical load.
There was not an awful lot we could turn off. We were in airspace underlying Class B, so we didn't want to turn off any nav lights, beacon, or strobes. Nor did we want to turn off the transponder. Although the plane had an auxiliary fuel pump, it was not used in normal conditions and we did not have it on. We did turn off unneeded avionics, such as the second nav/comm, DME, and ADF. We also dimmed down the panel lights and used red-lens flashlights to read the instruments.
Another factor is that on the missed approach, I actually forgot to retract the landing gear. This was a good thing, since the landing gear uses an electrically-driven hydraulic pump. Retracting the gear would have consumed a lot of power, and we might not have had enough left to get it down again. Manual extension would have worked, but I am glad it was not necessary.
We had no difficulties landing, though the radio was getting a bit crackly by then. I can't remember if we extended the (electric) flaps. Odd thing though, when I pulled the throttle to idle in the flare, the alternator came back online. Strange.

One thing that helps to inform a decision about how much load to shed when losing an alternator is to understand how much battery capacity your plane has. If you know your battery can power your equipment for a predictable amount of time, you can keep equipment running improving safety, communications and situational awareness.
Each year during my annual, I run a battery test capturing data from my G3X Touch PFD. I run this test with the full panel on, fuel pump off (high wing plane) and external lights off.
From my data, I estimate that my primary battery (yellow trace) will easily last an hour powering my full panel including radios, GPS IFR navigator, and transponder. The backup battery (blue trace) is not powering the preceding three items, but does power the non-IFR GPS in the G3X, will last for 6 hours - far longer than my fuel.

My school’s C172S POH promised 45 mins on the main battery, plus another 30 minutes for avionics on the standby battery.  I never tested them to confirm, but it did make me think about the problem differently.


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What is the different between an aircraft engine gearbox and an aircraft engine transmission?
For an aircraft engine, what is the difference between a gearbox and a transmission?
I was of the understanding that a transmission is a type of gearbox. For example, in a helicopter, a transmission is used in to convert horizontal rotation of the turbo-shaft to a vertical shaft rotation. Is an aircraft engine gearbox and aircraft engine transmission the same thing?
Are there other types of gearboxes used in aircraft engines besides the transmission design?

In aircraft, transmission usually refers to the whole system, that transmits power between two points, say between the MGB and the tail rotor. Gearbox is usually a component of the transmission system (along with shafts, for example) which is used for changing rotational speed.
In a sense, a full transmission system is found only in helicopters, and not in fixed wing aircraft. The closest thing a fixed wing aircraft has to a transmission is the variable pitch propeller, which is analagous to the car transmission.

By nydano - Cut away view of Hamilton Standard Propeller, CC BY-SA 2.0, $3
On the other hand, a number of aircraft have gearboxes, especially the turboprops (and some piston engines), for reducing the engine output speed before turning the propeller. The following image shows the gearbox in a GE turboshaft engine.

Image from mrlarry.org
Turbofan engines do have a gearbox, which is used to run the accessories. The compressor is usually run through a shaft from the turbine, with various turbine stages running various compressor stages, while some turbofans do use gears between turbine and compressor, called geared turbofans.
Aircraft transmissions (whether helicopter or fixed wing) is usually one speed from one point to another, with speed reduction (or direction change) offered by the gearboxes.

A transmission is something usually used on a car. They have multiple "gears" that allow the engine to rotate at the same speed while the output rotates at progressively higher speeds. Airplanes don't use transmissions (that I know of!).
A gearbox is simply a 1-gear transmission. I suppose technically it could be called a transmission. But it usually is reduction gearing that reduces the engine RPM to propeller RPM to increase the amount of torque produced by the prop. (ex: engine RPM of the turbine is 35,000 - while the prop spins at only 1700 RPM!)
Gearboxes are most commonly used on turboprops, but some piston engines, like Rotax, use reduction gearboxes.


text:
How are airline pilots assigned routes? Are there easy and tough ones?
How are routes given to airline pilots? Is it based on the amount of flying experience they have or just random or based on availability?
Also, can routes be classified into tough and easy? If so, what are some examples? In not, then are all routes equal? Doesn't more traffic in a particular area correspond to a harder route?

What type of flying are you asking about? I'm going to assume you are asking about professional pilots flying in commercial air operations. At one company I worked for, I was assigned several primary routes for a year, and covered other routes as able. At another company, I would be assigned a route hours or minutes before I would fly it. At other companies pilots might bid for routes based on seniority. There is a great deal of variation within the industry, both in terms of what kind of flying is done and how companies handle assignments.  Your question is unclear as currently asked.

The answers to your questions vary greatly depending on the individual airline, type of equipment, what kind of flying they do, as well as contractual and union (if any) work rules. The one thing that is generally the same and as noted in the previous answer and comment, is that scheduled lines of flying are published to the crews, and a bidding system based on seniority is used to assign those lines.

Also, can routes be classified into tough and easy?

What one pilot considers tough another may consider easy. A better way perhaps to think of it is that what one pilot considers desirable, another may not, and that will be reflected in how the individual pilots bid.
Some examples (but certainly not exhaustive): Young pilots with families would typically bid away from Christmas flying. I, however, not being a fan of Christmas and with all my children grown, deliberately bid to work on Christmas to open a no-work-on-Christmas line for someone else. In the northern hemisphere winter, I would bid into Australia, South America, or Africa because I don't like the short days of winter. In the northern hemisphere summer I tended to bid into places where I stood a good chance of getting to a beach. A lot of pilots bid simply to maximize income. And there were those who bid to maximize overnights at a place where they had an ongoing personal relationship.
Whether or not a pilot gets to actually fly a line as published is another matter. If you're flying for a scheduled airline that does no on-demand charter work, and you're going from one company station to another company station, chances are good that you'll get to fly the line as published. If, however, you're flying for a company that does on-demand charter work, the probability of flying the line as published goes down as the percentage of charter work goes up, and this is especially true with a mixed fleet of passenger and cargo aircraft. I flew for two commuter airlines, and I almost always flew my awarded bid line as published. Then I flew for two 747 carriers, both of which did a lot of on-demand charters. In the 12 years of flying for the 747 carriers, I rarely flew a line exactly as it was published. If was a matter of when you would have to depart from your line, not if.
There are companies that do nothing but on-demand charters. In those cases what you're bidding is not where you're going to fly, but which days you will be on-call.

Doesn't more traffic in a particular area mean more tougher?

Some would consider it tougher, some more fun. A higher workload certainly, but I always felt that was more fun. There's something addictive, at least for me, to running approaches in high-density traffic. It's quite exhilarating really.

Most airlines use a Preferential Bidding System to determine routes. Basically, pilots submit which routes they want to fly (based on location, schedule, etc.) and then a system assigns them routes, with more senior pilots having preference on getting their choices.

I will try to add an answer which is more directed towards the second part of your question, "are there easy and tough ones".
Just like there are certain airports with rather difficult approach and landing procedures which may require special instruction and familiarization of the pilots (some are even further restricted such that only the captain is allow to do the landing), the same is true for particular routes (i.e. airways) which are simply more challenging than others.
One example is 'L888' (sometimes called 'the silk route'), an important short-cut especially for some European carriers on the way to Hongkong or Guangzhou. It runs straight over the Tian Shan mountain range, north of the Himalaya, with very high Minimum Safe Altitudes in some parts. In case of an emergency forcing an immediate descent (like loss of cabin pressure) or a drift down (engine failure), there are only very few and spatially constrained escape corridors that allow a safe descent and diversion towards lower terrain. Therefore, flights on L888 require extensive planning both before and throughout the flight, and usually airlines will make sure that the crew has received a specific briefing and/or training for this sector.
Another example would be routes crossing the Intertropic Convergence Zone (ITC) e.g. on flights from Europe to South America, where especially challenging weather phenomena may occur.
Regarding the question whether more experienced crew will get those routes: at least for one major European carrier I am aware of, this is sort of true in the sense that all their crew will initially start out flying short-haul aircraft, and only after some years of experience they are promoted to long-haul and then exposed to these routes (of course, there may also be challenging short-haul sectors, requiring e.g. prior airport familiarization).
So, to summarize, yes, there are airports and routes which are more challenging than others, and both airlines and regulations will make sure that only pilots who are sufficiently qualified will get these routes. The crew scheduling departments will usually know which pilots have received said instruction courses and plan accordingly.


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Does the CF6 use Pneumatic Reverse Thrust from the APU's bleed air?
Does the A330's engine (the GE CF6) use only pneumatic power from the APU for reverse thrust? Please explain detailed. Sorry for my English.

So,what do you say exactly please explain

Then look at that   https://www.instagram.com/p/BR8n30DhliW/

Maybe pneumatic power are used only for tests not in flight?..on the video footage is from test

Okay , I'll research more exactly,thank you so much

Thrust reversers on high-bypass engines are airframe parts
The thrust reversers on a high-bypass turbofan such as the CF6 are treated as part of the nacelle, which is made by the airframer, as opposed to being part of the engine.  This is unlike target-type thrust reversers, which are treated as engine parts by and large.
Airbus uses hydraulic reversers by and large
The reversers on current Airbii (including the A330 that you ask about) are hydraulic.  This is in contrast to the B747 and the A300/310 which also use the CF6 engine and use pneumatic reversers (driven from high stage engine bleed air directly, not the general bleed ducts).

Related schematics in the A330 FCOM, page 1-70-70 P1.

Why the two i's on Airbii? It would just be "Airbi"


text:
Is lashing equipment considered part of a ULD?
How should a load controller state additional lashing equipment on a load sheet in the context of ULDs? Should the additional weight equipment be added to the ULD's contents, or added to the ULD tare weight? Listing the additional equipment as Equipment In Compartment (EIC) does not seem to be a possibility.

Is this a test question to which you're trying to find the answer?  Please explain what work have you done to attempt to answer this yourself, since "do my homework for me" questions tend to be very poorly received here.  Also, please don't use all capitals in your question, as that is also poorly received here (as it is nearly everywhere on the internet).

i glanced all AHM , if you have any reference will be accepted with wellcome.

To be rude to the person who tries to  help you is guaranteed to get you a bad reception.  If you took even 20 seconds to view Ralph's profile, you should see that he is a highly respected member of this community.  You might also learn something that would help you.  Good bye.

People seem to be reading a lot into a little here. The last sentence of the question is vague - especially in the original, pre-edit version - and it doesn't seem like an obvious test question to me. Furthermore, if that last sentence weren't there, how would the question be received? I suspect that people would be trying to answer it rather than assuming that the OP is trying to pass a test. But even if s/he is, the current balance of meta opinion is on the side of answering.

I would second Pondlife's comments. I would be slow to read too much into anything the OP has said here, since there does appear to be a language barrier, which I am quite sympathetic toward. I think it sounds like a good question. I don't know much about the subject of ULDs, so if anyone more knowledgeable can improve my cleanup attempt please do! @TomMcW, does this fall anywhere near your scope of experience?

@JonathanWalters I've never had to do load sheets. The only ULD's I've ever seen with extra lashing are the hazmat cans. They have nets inside them but I don't know how they account for it on the load sheet. I don't think the net is considered part of the container although they usually leave them inside when they get unloaded.

Normally I would put this as a comment since I retired in 1999, and I don't know what current practice is. However, this is a bit too long for a comment. Also, this is from memory and it's been a long time now, as it's from my experience with load sheet preparation in the late 1980s and the 1990s. If a more recent useful answer appears, I'll simply delete this.
Further, this answer only directly addresses the question's last sentence:

Listing the additional equipment as Equipment In Compartment (EIC) does not seem to be a possibility.

The airplane does not, of course, care whether the extra lashing weight is tare weight or content weight. What it cares about is the total weight at the ULD position, and that's what the weight & balance calculations (probably done by computer) will use, whether given as one value or two values (tare & content) that have to be added.
Just adding the extra weight to a compartment without specifying where in the compartment it is would effectively put it wherever the compartment centroid was. That would be correct only if the ULD happened to be at that position.
In actual practice it could be argued that just adding to a compartment rather than a position in that compartment would be acceptable in some instances. For example, let's say you're very close to max takeoff weight before the addition, but the c.g. is well within limits. The ULD locations would have been decided by the software (or manually by the loadmaster) to put the c.g. nowhere near the limits. Adding a few pounds of extra lashing might put you over max takeoff, but it's going to make little difference to the c.g.
All of the three cargo carriers I was involved with insofar as weight & balance were concerned simply listed the total weight at a position. No differentiation was made between tare and cargo. Thus the addition of extra lashing was simply added to that positions weight, usually by rerunning the software to get a new solution.
The most common reason I observed for adding extra lashing was that when loading the ULD to a position, they found that one or more of the floor locks to hold the ULD in position were broken. For such cases, the loading manuals specified how many locks could be inoperative and how much extra lashing there had to be. Frankly, that extra weight was often ignored, but it was sometimes accounted for.
I don't have a definitive answer as to whether extra lashing should be added to tare or content. That is irrelevant to the airplane, though I can well imagine that there might be a form somewhere that required such a split. If someone had asked me back when I working which it should be, I would have said that it should be added to the tare for the simple reason that the ULD is there to safely contain the content. If for some reason extra containment weight had to be added to make the ULD safe, that would seem to be tare weight to me.
And I imagine that a customer, who had paid money for a certain amount of weight to be shipped, found out that because of broken parts on the airplane he had to pay more, he would not be happy.
A thorough search of the weight & balance manuals for aircraft might yield additional relevant information. Some such manuals for 747s and 767s can be found at http://terryliittschwager.com/wbmanuals.php


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How much lift must a helicopter rotor produce?
How much lift must a typical helicopter rotor produce? For example, consider the rotor of what seems to be a common helicopter: the Robinson R22. Is the lift produced equal to one of the following:

The weight of the helicopter;
Double the weight of the helicopter; or
Simply some value greater than the weight of the helicopter?

For example: for a 700kg helicopter, what maximum lift will the helicopter rotor need to produce?

In order for it to fly, it has to produce more lift than weight...

This may be a little too broad. Depends on the phase of flight. In a hover (ignoring ground effect and some other factors), the lift produced must exactly equal the weight of the craft. For a climb, the lift produced must be greater, how much so depends on how fast you want to climb. Conversely, to descend, lift should be less than weight, again the extent depends on how fast you want to go down...

This may be better suited for physics.se

The QE already knows that the (maximum) weight of the helicopter must be lifted. Now, the question is what is the minimum required vertical acceleration performance, and what margins are required. What other parameters play a role, max. service altitude, etc. ?  The question is not that broad.

My answer was wrong, because I forgot a simple concept which is that the initial force required would be more (from rest, to lift the craft) that it would be to further lift the craft.

@Ron Beyer, your answer is only correct for take-off, not for steady flight or descent.

In the hover, it must produce a lift force equal to the weight of the helicopter, in order for the helicopter to remain at constant altitude. A helicopter with a mass of 700 kg must produce a lift of 700*g = 6,867 N to hover at constant altitude.
In forward flight at constant altitude, the rotor must produce more thrust with the thrust vector tilted forward at angle α. Vertical thrust component = lift must be equal to weight for the helicopter to fly at constant altitude. As the helicopter picks up speed, less power is required to provide the same amount of thrust due to reduction of induced drag - if power is not reduced, the helicopter starts to climb when transferring from hover to forward speed.
If in the hover the rotor produces more lift than the weight, let's say 710*g,it accelerates upwards, resulting in a vertical velocity component that results in an additional aerdynamic damping force, proportional to vertical speed, caused by change of rotor blade Angle of Attack and fuselage vertical drag. So for a 700 kg helicopter with a rotor that exerts 710*g = 6,965 N, the extra 98 N is used for overcoming aerodynamic drag associated with vertical speed.
Assuming that by "lift" only the vertical component of thrust is meant: more lift than weight results in a constant upwards velocity. Less lift than weight results in a constant downwards velocity, even in a free fall (terminal velocity).


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Is there a procedure to safely handle a PED battery problem on a commercial flight?
On a recent flight, I heard a (somewhat unsettling announcement) from the flight attendant (paraphrasing from memory):

Dear passengers, if you currently have a Samsung Galaxy Note 7 device in your possesion, we kindly ask that you turn your device off completely and make no attempt to charge your device while in flight. If you see or smell smoke or hear unusual noise coming out of your device, alert a member of our staff immediately.

(at the time, I had no idea what this is about, but apparently the device was recalled due to a faulty battery)
I'm curious at this point, in the unlikely event of a (normally-safe) device like this displaying symptoms of imminent fire or explosion hazard, how would the staff react after being alerted of it? Is there a standard procedure for something like this?

On a flight where a Galaxy Note 7 caught fire, the flight attendants used fire extinguishers on it and dumped it in a bucket of water for the remainder of the flight. Using water on a lithium fire isn't a course of action I would have guessed to be appropriate but that's what they are reported as doing.

I have edited the title question to reflect the actual question posed by the OP, since the original title question, Is there a procedure to safely handle a dangerous object on a commercial flight? is properly answered by FAA regulations 14 CFR 135, Subpart K and 14 CFR 121, Subpart Z, etc. and the equivelant regulations by jurisdiction.

taking into account a "unlikely event of a (normally-safe) device" is one reason explaining the current safety level of commercial airlines operations. I'm quite confident many unlikely events could be handled by specific safety procedures included in flight attendant formation.

As a curiosity - I had heard NOTHING of the "worldwide news!" about this Samsung device, and I was interested to hear the announcements on getting on some flights: http://travel.stackexchange.com/questions/79368/why-is-the-samsung-galaxy-note7-banned-in-flight

@RedGrittyBrick: the problems with lithium batteries is thermal runaway, and what is burning is usually the electrolyte, so a big load of water for cooling it down is quite appropriate, as the water doesn't come into contact with large surfaces of lithum easily in that situation.

@PlasmaHH: Thanks for clarifying that. Good to know.

@RedGrittyBrick: The device that you are referring to was a Galaxy Note 2, over four years old at the time of the incident, and not related to the current recall of the Note 7. That the device was also a Note is a coincidence.

@dotancohen: Thanks for clarifying. I misremembered. I imagine airline staff might treat a smoking/burning Note 7 the same as they have a smoking/burning Note 2 though.

FAA Advisory Circular 120-80A contains recommended crew member procedures and training for combating in-flight fires. It has information about causes, indications and procedures of in-flight fire fighting. According to the AC,

Upon discovering a fire, the initial focus should be on aggressively
  extinguishing the fire with a readily available extinguisher (which will likely be halon), but do not use water if it is believed the fire is of aircraft electrical system origin. Generally, you should consider using the first available extinguisher rather than delaying your firefighting efforts while you locate a particular extinguishing agent for a class A, B, or C fire.

Airbus Flight Operations Briefing Notes- Managing In-Flight Fires also says pretty much the same thing:

Any fire, no matter how small, may rapidly become out of control, if not  dealt with quickly.The first priority will always be to put it out.

Coming to the Galaxy Note 7 issue, the AC says,

h. What are the Recommended Procedures for Fighting a Lithium Battery Fire? The following procedures are recommended for fighting a fire in a lithium-type-battery-powered PED. The procedures consist of two phases: extinguishing the fire, and cooling the remaining cells to stop thermal runaway.
(1) Utilize a halon, halon replacement, or water extinguisher to extinguish the fire and prevent its spread to additional flammable materials.
(2) After extinguishing the fire, douse the device with water, an aqueous-based extinguishing agent, or other nonalcoholic liquids to cool the device and prevent additional battery cells from reaching thermal runaway.

Though the standard procedures in case of a fire has to be decided by the company, the FAA recommends some procedures to be followed, like:

• Be aggressive; if flames are visible, fight the fire immediately.
• Someone must immediately notify the flight crew to describe the fire, smoke, smells, action being taken,  etc.
• If flames are not visible, find the base or source of the smoke.
• Pull circuit breakers, in applicable area.
• Do not reset circuit breakers, unless instructed by flight crew.
• Relocate passengers as necessary.
• Locate hot spots using the back of your hand.
• Don PBE (not necessarily in this order).

The flight crew (who are supposed to don their oxygen masks on indication of smoke/fire) are supposed to inform the ATC and plan for an emergency landing, if necessary.

This answer would be better if the acronym "PBE" was explained.

In context, that's probably Personal Breathing Equipment.

There is plenty of incidents (and some reports of recommendations being published) to be found on AvHerald. Always handled as outlined above and so far without serious injury.


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How does jet engine water injection work?
How did the "wet takeoff" of old days work? Was the water used ordinary distilled water, or did it have additives? Where is it carried in the aircraft?

What are "leaky jets"? You mean the water injectors?

Related discussion of water injection, although not really a duplicate as it addresses some aspects of water injection, but in the context of injection vs contamination.  This question asks for a more complete treatment of the topic than what is presented there.

"Leaky jet" is reference to low and very low bypass turbofans, like the JT8. Water injection and leaky jets kind of shared the same technological age, that's why they relate to each other.

@GermanoCavalcanti: Early 747-100s also used water injection, despite their high-bypass engines.

On many early jet airliners water was sprayed it into the engine air intake or compressor where evaporation cooled the air and allowed cooler, denser air to be ingested by the engine. The result was increased thrust, especially needed for operation from hot and high airfields, or a cooler temperature in the hot section of the engine at the same thrust. From SAE Paper Number 2004-01-3108:

Water injection was first used over 45 years ago on commercial
  transport aircraft to increase thrust. Boeing 707-120 aircraft with
  Pratt & Whitney JT3C-6 engines and later, the Boeing 747-100 & 200
  aircraft with Pratt & Whitney JT9D-3AW and -7AW engines, all used
  water injection for thrust augmentation.

This report discusses various techniques for water injection:

ahead of the low pressure compressor. This is the common method for thrust increase in hot and high conditions.
ahead of the high pressure turbine. This is used in cold weather, when injection ahead of the low pressure compressor would run the risk of ice accretion.
together with fuel into the combustor. This technique is commonly used with stationary gas turbines in order to reduce nitrogen oxide emissions.

And NASA-TM-2010-213179 is more specific on the system:

Four water-injected Pratt & Whitney JT3C–6 engines were used on early
  Boeing 707–120 Stratoliner aircraft to augment takeoff thrust on days
  above 20 °F. This system used a belly tank to store demineralized
  water and an electrically driven boost pump to deliver water to the
  four engines. At that point, an engine-driven mechanical pump
  increased the pressure to about 400 psi for injection before the
  low-pressure compressor (LPC) on days as cold as or colder than 40 °F
  and for injection into the high-pressure compressor (HPC) only on days
  between 40 and 20 °F.

What would happen if kerosene instead of water was filled into the water tanks was tried out by a BAC-111 on September 6, 1971:

The aircraft collided with a bridge, shearing off both wings, after a
  double engine failure occurred during takeoff. The water-injection
  system to cool the engines during takeoff was inadvertently filled
  with kerosene instead of water.

More recent work on water injection focused on the reduction of nitrogen oxides which form in lean combustion and high temperature. By lowering the temperature level of the combustion process, the nitrogen oxide pollution can be greatly reduced.

How did the kerosene injection cause the engines to flame out?  I have a hard time picturing how that would work... if water is okay to put into the engine at that point, why is a little more fuel a bad thing?

@RalphJ Reports say they noted an increase in engine temp during the takeoff roll. Injecting fuel in the compressor stages ahead of the burners would almost certainly result in early combustion and surge.

Extra fuel probably raised the temperature above material capacity; at some point the pieces might had melt and changed their shape and center of mass, colliding with other parts or vibrating the system to a fail point.

I've gone ahead and changed your date from June 9 to September 6. It's given as "9/06/1971" in the page you link, which seems to use mm/dd/yyyy dates; see also Paninternational Flight 112 on Wikipedia.

@TannerSwett: Thank you!

I offer this as an adjunct to Peter Kämpf's answer above.  The simple explanation is that the injected water evaporates during the compression stages, and this cools the air (think sweat evaporating cooling your skin on a hot day).
Short answer
Water injection gives the jet engine the ability to do more work for a short time without exceeding the design limitations of the engine in extreme conditions.
Turbine engineering
Jet engines were / are designed and built to specifications and tolerances based on the materials used.  The "design thrust" is usually the static thrust the engine is capable of given standard conditions (i.e. static air temperature, atmospheric pressure, humidity, etc.).  But when it's hot outside, the design thrust is sometimes insufficient for the aircraft weight / runway length / wind conditions, etc., and airlines don't like having to bump pax / cargo off the plane for being unable to get airbornea.  Water injection is a method to mitigate this scenario.
Physics of how injecting water gives more thrust
Understanding the ideal gas law, $PV = nRT$, is key to this discussion.  As Peter stated, by cooling the air ($\downarrow T$), then something on the left side of the equation also has to decrease. ($R$ is a constant.)  This has to be pressure ($P$), as the volume ($V$) inside the combustion chamber doesn't change (at least we'd hope it doesn't!).
But here's a twist:  Adding water vapor to air lowers its density.  Since density is mass (number of molecules $n$) divided by volume $V$, and again, the volume isn't changing, then this implies $\downarrow\!n$b.  Now, we have $\downarrow\!PV = \downarrow\!nR\downarrow\!T$.
So, how do we increase the density to the air coming into the hot section as Peter mentioned?
Water injection $\Rightarrow$ burn more fuel
To increase density, one needs to cram more molecules into the given volume.  The only way to do that in an internal combustion turbine is to increase the fuel flow, thereby increasing the intensity of the combustion process, and causing more air to be sucked into the hot section.  The water injection merely gives the engine the ability to do more work without exceeding the tolerances of the engine in extreme conditions.
Note that the water injected has completely evaporated into vapor prior to reaching the hot section.  While the water molecules don't contribute to the combustion process (obviously), there isn't so much of it to hamper it, either.
The "water injection era"
I sometimes think water injection was merely an engineering "hack" to help bridge the technology gap between the large, modern airframes of that era, and the puny engines used to fly them.
Granted, metal airframe construction dates to the late 1920's, and jet engines didn't appear until around 15 years later.  So, by the late 1950's, airframes were modern and state-of-the-art, but jet engine technology was severly lackingc.
The military dealt with this by bolting on more and more enginesd,e.  However, this was impractical for commercial airline service, so any available engineering "trick" had to be employed to accommodate the newer airliners.
Finally...
Lest I get flamed to a crisp for the above invective, let me just say that the "water injection era" needed to happen.  Think about it:  the Boeing 747 was the worst thing and the best thing to happen to jet engine development.  The modern turbine engines these days are engineered for the "extreme" conditions mentioned above (no need for water injection), and cool gadgets like FADEC help keep them running clean and efficiently.

a But, airliner manufacturers do like to advertise the capabilities of their products (as do jet engine manufacturers).  I mention this in particular because it seems that the 1960's and early 1970's saw a big increase in promoting air travel on a cultural and societal level yet it seemed as if the technology couldn't keep pace.
b Actually, the number of molecules isn't changing so much as the average molecular weight of all the molecules.  Again, see this link for more info.
c I base this assertion on how the Boeing 747 program was delayed repeatedly because of problems with the JT9D development.
d and water injection.  Note that I intentionally leave out afterburning as a "trick" in this context as it is often used in multiple stages of flight--i.e. it's not a one-time-use only procedure.
e B-52's, anyone?  Or how about the B-36?

You seem to be saying that the military's response to underpowered engines was to use more of them, and the civilian response was to use water injection. The military made extensive use of water injection.

@DavidRicherby: thanks for the feedback; perhaps I was unclear about that. I am aware of the military use of water injection... But, my point still stands that a whole bunch of little engines for a commercial airliner doesn't make much practical sense.

Thank you, @pr1268; your answer was indeed a nice supplementation covering additional aspects about this topic.

Water injection is used on the Rolls-Royce Pegasus engine on the Harrier jump jet, but it has nothing to do with combustion. Instead, water is injected to cool the turbine blades to temperatures that allow the engine to operate at full rated power.

The maximum take-off thrust available from the Pegasus engine is
  limited, particularly at the higher ambient temperatures, by the
  turbine blade temperature. As this temperature cannot reliably be
  measured, the operating limits are determined by jet pipe temperature.
  To enable the engine speed and hence thrust to be increased for
  take-off, water is sprayed into the combustion chamber and turbine to
  keep the blade temperature down to an acceptable level.
Water for the injection system is contained in a tank located between
  the bifurcated section of the rear (hot) exhaust duct. The tank
  contains up to 500 lb (227 kg, 50 imperial gallons) of distilled
  water. Water flow rate for the required turbine temperature reduction
  is approximately 35gpm (imperial gallons per minute) for a maximum
  duration of approximately 90 seconds. The quantity of water carried is
  sufficient for and appropriate to the particular operational role of
  the aircraft.
Selection of water injection engine ratings (Lift Wet/Short Lift Wet)
  results in an increase in the engine speed and jet pipe temperature
  limits beyond the respective dry (non-injected) ratings (Lift
  Dry/Short Lift Dry). Upon exhausting the available water supply in the
  tank, the limits are reset to the 'dry' levels. A warning light in the
  cockpit provides advance warning of water depletion to the pilot.

If you run out of water on a Harrier, you will have serious problems trying to keep the engine from frying itself in anything other than conventional flight. No VTOL after that.

This is really pretty much another supplement to Peter Kampf's answer, trying to clarify part of the answer that I found a bit unclear. Specifically, he quotes a section saying:

At that point, an engine-driven mechanical pump increased the pressure to about 400 psi for injection before the low-pressure compressor (LPC) on days as cold as or colder than 40 °F and for injection into the high-pressure compressor (HPC) only on days between 40 and 20 °F.

At least to me, those temperature ranges don't seem to make a whole lot of sense.
At least according to the KC-135 flight manual (T.O. 1C-135(K)A-1) you used dry thrust below 20F, injected heated water between 20 and 40 F, and unheated water between 40F and 100F.
For those interested in the nitty-gritty details:

The injection of water ahead of the combustion chambers will cool the airflow, thereby increasing it's density  and potentially allowing more fuel to be burned, increasing power. Water injection ahead of the high pressure turbine will have the effect of cooling the turbine, which may permit use of a higher power setting, and the mass of the water will be added to the mass flow rate through the engine, directly increasing thrust.

water molecules do contribute in the combustion process, since in the turbine the temperatures and pressures reach the thermolytic ratio for water ignition.
At 1  bar that temperature is 5600C. At elevated pressures, the temperature is reduced subsequently, since volume remains the same, by n is increased relatively.
At BAC-111 the crash incident was due to luck of thrust since no water spray was made available.

The 6 September 1971 BAC-111 crash? Wikipedia says it was caused by jet fuel in the water injection system, quite different from what you write. Also, could you elaborate on how exactly does "water ignition" [sic] work? What exactly would be oxidized in this reaction?